On 15/06/2007, at 6:38 AM, Markus Innerebner wrote: > Hi > > I did not read the book, but I am gonna do it soon. It is a must. :-)
>> >> From section 14.7 of Ron Lake's GML book: >> >> "Each time slice includes a subset of feature properties - those >> properties that change over time... This approach often leads to a >> more economical representation of a dynamic feature." > economical representation? Does the author mean i.e. the > observation of stock or something similar? This is something new > for me. Anyway it is good, that I get new different informations > from you ;-) >> >> "The track property is a specific kind of history, defined in GML >> 3, for modeling dynamic features that represent moving rigid >> objects, such as a person, ground vehicle, a boat or an aircraft." >> >> ...so I'm thinking that MovingObjectStatus is more appropriate >> given its higher level abstraction and thus consistent form for >> expressing movement. The GML book says to me that time slices are >> good for showing what properties have changed since the last time >> slice - not necessarily just those properties that relate to >> movement either. > So this means as well trucks as well buses should be modeled with > the element MovingObjectStatus. I would suggest so. > I remember in GML 3.1 spec. there is an example of > MovingObjectStatus that models > > Citation of GML 3.1 >> If the feature represents a moving object such as a ***g**round >> vehicle* or a ship, then the track property >> comprises a sequence of MovingObjectStatus elements. For example, >> a dynamic feature such as a cyclone >> may have a gml:track property such as shown in the following >> fragment:* >> * > And buses or trucks make part of the class ground vehicle . > > <gml:track> > <gml:MovingObjectStatus> > <gml:validTime><gml:TimeInstant> > <gml:timePosition>2005-11-28T13:00:00</gml:timePosition> > </gml:TimeInstant></gml:validTime> > <gml:location><gml:Point> > <gml:pos>140. -35.</gml:pos> > </gml:Point></gml:location> > <gml:speed uom="#kph">12.</gml:speed> > <gml:bearing> > <gml:CompassPoint>SE</gml:CompassPoint> > </gml:bearing> > </gml:MovingObjectStatus> > <gml:MovingObjectStatus> > <gml:validTime><gml:TimeInstant> > <gml:timePosition>2005-11-28T14:00:00</gml:timePosition> > </gml:TimeInstant></gml:validTIme> > <gml:location><gml:Point> > <gml:pos>140.1 -34.9</gml:pos> > </gml:Point></gml:location> > <gml:speed uom="#kph">23.</gml:speed> > <gml:bearing> > <gml:CompassPoint>ESE</gml:CompassPoint> > </gml:bearing> > </gml:Moving Looks good to me. > Than I found in some other documents the model of a bus with > TimeSlice. I don't think there's anything wrong with that - there are many ways to express the same thing. MovingObjectStatus just provides a common means of describing things that move rather than one coming up with one's own schema. > I think I would trust more the statements of the specification and > this Book. So I will immediately change the example in my paper. > > Thanks a lot for this suggestion. Thanks for this dialogue; it has been most enjoyable. Kind regards, Christopher ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Mapbuilder-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mapbuilder-users
